<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>typeof方法</title>
</head>
<body>
    
</body>
<script>
    let l1 = true;
    document.write(typeof(l1) + "<br>");    // boolean

    let l2 = null;
    document.write(typeof(l2) + "<br>");    //    object  js原始的一个错误

    let l3;
    document.write(typeof(l3) + "<br>");    // undefined

    let l4 = 10;
    document.write(typeof(l4) + "<br>");    // number

    let l5 = "hello";
    document.write(typeof(l5) + "<br>");    // string

    let l6 = 100n;
    document.write(typeof(l6) + "<br>");    // bigint
</script>
</html>